Abstract
Purpose of the study: Opinions vary concerning results after knee arthroplasty with preservation of the posterior cruciate ligament (PCL) in patients with rheumatoid disease. We report our findings in patients reviewed more than ten years after implantation in comparison with patients treated for osteoarthritis.
Material and methods: One surgeon implanted 43 knee arthroplasites (Kali) with preservation of the PCL (9 bilateral cases) in 31 women and 3 men, mean age 53 years (range 30–70 years). Outcome was assessed with the AKS clinical and radiological scores. Passive recur-vatum and posterior drawer at 90° flexion were measured radiographicaly at last follow-up. Outcome was compared with the results observed in a control group of 29 prostheses of the same type implanted for osteoarthritis (among a total of 203 implantations).
Results: There were no patients lost to follow-up: two patients were removed from the analysis due to infection on early wound necrosis and late metastatic infection. Eleven patients (16 prostheses) died before ten years follow-up; outcome was satisfactory for the prosthesis. Twenty-one patients (25 prostheses) were reviewed at more than ten years, mean follow-up 136 months. There was one case of supracondylar fracture which healed without sequela after osteosynthesis. The mean knee score was 34.3 preoperatively and 87.2 postoperatively with a mean function score improvement from 17 to 44 points. The pain score (47.3 points on average, was significantly improved while joint range of motion remained unchanged (117°). There were no worrisome lucent lines. Mean recurvatum measured radiographically was 6.9° (range 3–14°) and mean posterior drawer at 90° flexion was 4.2 mm. Outcome in the control group was the same excepting (p< 0.05) for lesser range of motion (109.7°) and better function score (62 points). Laxity (clinical and radiographic scores) were the same.
Discussion: The results obtained in patients with rheumatoid disease were satisfactory and the same as those obtained in patients with osteoarthritis and were comparable to those with prostheses sacrificing and replacing the PCL. There were no cases of prosthesis loosening. Complications were very limited and less frequent than among the entire population of 203 prostheses for degenerative disease.
Conclusion: Ligament alterations are not a contraindication for preservation of the PCL in patients with rheumatoid arthritis. Irrespective of the etiology, the main limitation on prosthesis longevity is polyethylene wear observed beyond ten years (ten changes of the plateau because of wear among 246 prostheses).
Correspondence should be addressed to SOFCOT, 56 rue Boissonade, 75014 Paris, France.
